The present invention disclosed herein relates to a wireless communication system, and more particularly, to a beam forming device forming a beam through the control of an antenna array and a method for forming a beam by using the same.
To obtain a geographical coverage serviced by wireless communication systems, the array antenna elements may be controlled in inclination. There are methods for controlling the inclinations of the array antenna elements, which include a method for controlling the positions of the antenna elements to make an inclination mechanically and a method for phase-shifting the signals that are provided or received into the antenna elements to make an inclination electrically.
Since the beam is formed according to the accuracy of the amplitude and the phase of each of RF signals that are supplied into array antennas, the method of making the inclinations of the array antennae mechanically may have a complex structure due to increases of costs, volume, and weight according to needs of the tolerance and accuracy of a phase-shifter.
Also, the method of making an inclination of the array antennae electrically may control each phase of the antenna elements after a power-amplifier. However, due to the non-linearity of the power amplifier, there is a limitation that it is difficult to accurately control the beam of the antenna.